MacOSX + Boost_Python + PyFTGL :- Symbol not found, expected in: flat namespace

问题

I am trying to install PyFTGL on MacOSX Yosemite.

The python version I am using is 2.7 from macports. I have installed boost from macports specifying +python27.

To install PyFTGL I built from source and edited the setup.py file from:

module_ftgl_libs = [
    'GLU',
    'GL',
    'freetype',
    'z',
    'ftgl',
    'boost_python',
    ]

 module_ftgl = Extension(
    'FTGL',
    module_ftgl_src,
    include_dirs=module_ftgl_include_dirs,
    libraries=module_ftgl_libs
    )

to:

 module_ftgl_libs = [
    'freetype',
    'z',
    'ftgl',
    'boost_python',
    ]

 module_ftgl = Extension(
    'FTGL',
    module_ftgl_src,
    include_dirs=module_ftgl_include_dirs,
    libraries=module_ftgl_libs,
    extra_link_args=['-framework', 'OpenGL', '-framework', 'GLUT']
    )

I then build the setup.py file and copy the resulting FTGL.so file to the same folder as my python code test.py which uses the FTGL functions.

My problem is when I now run my code I get the following error:

Traceback (most recent call last):
  File "test.py", line 29, in <module>
    import FTGL
ImportError: dlopen(/Users/james/Desktop/test/FTGL.so, 2): Symbol not found:__ZN5boost6python7objects15function_objectERKNS1_11py_functionERKNSt3__14pairIPNS0_6detail7keywordESA_EE
  Referenced from: /Users/james/Desktop/test/FTGL.so
  Expected in: flat namespace
 in /Users/james/Desktop/test/FTGL.so

I don't know much about linking, setup.py files and boost and I have spent a long time researching on both Google and Stack Overflow but now I can't figure out the problem.

回答1:

Using c++filt, the symbol can be decoded as:

$ c++filt -n _ZN5boost6python7objects15function_objectERKNS1_11py_functionERKSt4pairIPKNS0_6detail7keywordES9_E
boost::python::objects::function_object(boost::python::objects::py_function const&, std::pair<boost::python::detail::keyword const*, boost::python::detail::keyword const*> const&)

Since I have the same issue, I looked for similar symbols in the libboost_python.dylib:

$ nm -gU ~/Downloads/boost_1_60_0/bin.v2/libs/python/build/darwin-4.2.1/debug/libboost_python.dylib | grep function_object
0000000000027cd0 T __ZN5boost6python7objects15function_objectERKNS1_11py_functionE
0000000000027c20 T __ZN5boost6python7objects15function_objectERKNS1_11py_functionERKNSt3__14pairIPKNS0_6detail7keywordESA_EE

One of which decodes as:

boost::python::objects::function_object(boost::python::objects::py_function const&, std::__1::pair<boost::python::detail::keyword const*, boost::python::detail::keyword const*> const&)

The only difference is that the boost dynamic lib uses std::__1::pair instead of std::pair.

As also mentioned here: Why can't clang with libc++ in c++0x mode link this boost::program_options example?, libc++ and libstdc++ are not compatible. One option is to recompile boost with libstdc++:

./b2 cxxflags="-stdlib=libstdc++" linkflags="-stdlib=libstdc++" python

回答2:

I was able to overcome this error by uninstalling all boost libraries then using brew install boost155 --with-python --with-mpi --without-single and switching from homebrew gcc/g++-5 to gcc/g++-4.9

go to brew edit boost155 and replace the layout from tagged to system if possible

来源：https://stackoverflow.com/questions/29777337/macosx-boost-python-pyftgl-symbol-not-found-expected-in-flat-namespace

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python

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